This invention pertains to improvements in the construction of closed cycle parts washers of the kind which recirculate a cleaning solution or solvent from a sump onto a part to degrease and clean it.
Parts washers, which are capable of removing contaminants such as, oil and grease based dirts from metal or other parts which must be cleaned,, are widely used in such industries as automobile and truck repair, machine shops, manufacturing operations, shipboard (marine), oil field operations, aircraft and helicopter repair, construction, overhaul facilities and other facilities.
Parts washers are of a fairly uniform design: a sump containing cleaning solution is supported by legs or other supports. The washer is usually made of metal. Parts to be cleaned can be placed on racks within the sump to hold or support the parts. Some parts are held by hand, if desired. A recirculating pump, with some external control for actuation by the user, provides a continuing spray of the cleaning solution from the sump for flushing and cleaning the part.
For safety reasons, if the cleaning solution is a hydrocarbon solvent, the solvent is required to have a flashpoint of 104 degrees F. or higher. Since such solvents represent a significant flame hazard, parts washers of the types described are uniformly provided with a completely enclosing (metal) lid which is supported in the "up" position to provide access to the washer, but which includes some form of thermally sensitive or fusible link in the support so that if in the event of a flash fire, the link fails, dropping the lid across the bin, smothering the flames.
Environmental restrictions, especially on the disposal of hazardous waste products, require that such solvent be recirculated and reused. This poses obvious solvent contamination problems after the first use. The prior art has been to place various forms of filter in the line between the recirculating pump and the nozzle. However, as the recirculation pump is only activated when a spray is required for part cleaning, filtration only occurs for a short period of time during actual cleaning use. This has proven insufficient to remove residual contaminants and debris from the solvent, and the solvents still require periodic flushing, draining and replacement, all of which pose significant environmental problems to the use, storage, and disposal of the waste contaminated solvent.